Selective reduction gear



Oct. 28, 1930. PARKER ET AL SELECTIVE REDUCTION GEAR Filed Feb. 25, 1928 4 Sheets-Sheet 1 Oct. 28, 1930. c. J. PARKER ET AL SELECT-IVE REDUCTION GEAR Filed Feb. 25, 1928 4 Sheets-Sheet 2 flTTUR/VE/ Oct. :28, 1930. J PARKER ET AL l,7 79; 824

SELECTIVE REDUCTION GEAR Filed Feb. 25, 1928 4 Sheets-Sheet 3 Oct. 28, 1930.

4 Sheets-Sheet 4 c. J. PARKER ET AL SELECTIVE REDUCTION GEAR Filed Feb. 25, 1928 mzzziz ei ErecuinX,

Patented Oct. 28, 1939 warren sraras PATENT orrics CYRUfi J. PARKER, DECEASED, LATE OF PORTLAND, OREGON, BY MARY EVANS PARKER, EXECUTRIX, OF PORTLAND, OREGON, AND WILLIAM O. JOHNSON AND HASKELL G.

CARTER, OF PORTLANROREGON, ASSIGNORS TO IRON comm, OF PORTLAND, OREGON, A CORPORATION manuals murac'rumne SELECTIVE REDUCTION GEAR Application fled February 25, 1928. Serial No. 257,051.

This invention relates generally to under feed stokers for burning crushed coal and particularly to a select1ve reduction gear adapted to be placed between the motor and the fuel feed screw commonly employed in such devices.

The main object of this invention is to provide a quiet running, vibrationless reduction gear having a plurality of selective speeds.

The second object is to secure a complete uniformity in the distribution of load imposed by the fuel feed mechanism upon the driving motor. J

The third object'is to construct a selective reduction gear which will be easy to manufacture and maintain and not affected by improper or careless handling.

The fourth object is the production of a selective reduction gear having a wide range of speed ratios and a relatively small size and low weight with relation to its power transmitting capacity.

These, and other objects, will become more apparent from the specification following as illustrated in the accompanying drawings, in which;

Figure 1 is a front elevation of the device. Figure 2 is a longitudinal section taken along the line 22 in Figure 1. Figure 3 is a vertical section through the locking lever and its mounting. Figure 4 is a vertical section taken along the line 4-4 in Figure 2 showing the position of the gears for the slowest feed. igure 5 is a fragmentary section showing the relation of the gears when in an intermediate position. Figure Sis a view similar to Figure 5 showing the relation of the gears in the high speed position. Figure 7 is a fragmentary view showing the shape of the teeth in certain of the gears. Figure 8 is a perspective view of the device showing its relation toan under-feed stoker. Figure '9 is a vertical section taken along the line 99 in Figure 2. Figure 10 is a horizontal section through the fuel feed hopper and fan casing showing the device and its drive motor in elevation.

Similar numbers of reference refer to the a damper (not shown similar parts throughout the several views. Referring in detail to the drawings, in order to illustrate the use of this device and the reasons for its peculiar construction there is shown the outline of a furnace 11 into which projects the tuyeres 12 of an under-feed stoker whose fuel feed screw 13 in a ductl l' carries coal 15 in crushed form from the hopper 16 into'the combustion z one. A fan 17 is provided which supplies air through the casing 18 to the tuyeres 12. A high pressure air pipe 19 extends from the point of high velocity in the fan casing 18 to the top side of the fuel feed duct 14 for the purpose of preventing the generation and backing up of the gases within the fuel duct 14. The pipe 19 is preferably provided with a cut-off valve'20 and the casing 18 is provided with slow movement which must be capable of being varied within certain limits, whereas the fan itself can be operated-at a moderate speed and its output controlled by dampers or similar devices as above suggested.-

Turning now to the device itself it consists of a somewhat cylindrical housing 22 whose feet 23 may be secured to a convenient su port 24. On the side of the housin 22 1s built a motor bracket 25 upon w ch is mounted the motor 21. The motor shaft 26 is provided with a flexible coupling 27 which joins same to the shaft 28 which is mounted on the ball bearings 29 within the top portions of the housing 22. The shaft 28 has formed in the middle portion thereof a worm 30 and the end 31 of the shaft 28 passes through the fan casing support 32 to which attached the fan casing 18, the fan 17 beme mounted upon the end 31. A curved extension 33 of the housing 22 extends upwardly above the worm 30 and forms a supportsame a spacer sleeve 36 in front of which is a countershaft gear 37 provided with a forwardly extending hub 38 provided with a shear pin 39 which passes through the shaft 34 and eliminates danger of overloading the device in case the fire should become extinguished and attempts were made to feed coal into the combustion zone without consuming same. It is preferable to square the end 40 of the shaft 34 to receive a wrench which will permit the realining of the parts 34 and 38 for the insertion of a new pin 39 or to permit hand feeding as when starting a fire. On the rear side of the bearing 35 and ke ed to shaft 34 is a countershaft pinion 41 w ich meshes with the fuel screw drive gear 42 which is mounted on the hub 43 on the back 44 of the housing 22. A flanged shaft 45 is connected to the gear 42 by means of the dowel pins 46 a and its squared end 47 is connected to the shaft 48 of the fuel feed screw 13 by means of the couplings 49. The back cover 50 forms a bearing for the rear end of the shaft 34 as well as forming a dust guard around the shaft 45. The back cover 50 is joined to the fuel feed duct 14 by means of the bracket 51. Coaxial with the gear 42 is mounted a gear cage shaft 52 whose rear end is supported in the ball bearings 53 on the back 44 and Whose front end is carried by the ball bearin 54 within the hollow portion 55 of the hu 56 of the ear cage front 57 which is joined to the bao 58 by the webs 59. The back 58 is supported by ball bearings 60. On the shaft 52 is keyed a worm wheel 61 which meshes with the worm 30 on the shaft 28. On the shaft 52 is also secured the wide faced drive pinion 62 preferably having teeth in the form shown in Figure 7. Disposed around the gear cage are mounted the high speed gear 63, the intermediate gear 64 and the slow speed gear 65 on the shafts 66 67, and 68 respectively.

The gears 63, 64 and 65 are constantly in mesh with the pinion 62. The gear 63 serves as an idler and can be brought in mesh with the gear 37 by rotating the gear cage whose front 57 is provided with six index holes 69 and 70 adapted to receive the locking pin 71 which is slidably mounted on the front cover 72 and is provided with a spring 73 normall urging the pin 71 into a locking position. if locking lever 74 is rovided by means of which the pin 71 may e temporarily withdrawn to permit the rotation of the gear cage and when the pin 71 occupies any one of the holes 70 the device is in gear and when the pin 71 occupies any one of the holes 69 the device is in a neutral position. For the purpose of rotating the gear cage a turning knob 75 is provided which for convenience is made somewhat triangular dicating the particular speed being used. Re-- K turning again to the gear cage; there is mounted on the shaft 67. the intermediate gear 64 which meshes with the pinion 62 and has mounted alongside of same an intermediate pinion 82 which if properly positioned by the rotation of the gear cage can also mesh with the gear 37. This combination of gears provides an intermediate speed. On the shaft 68 which carries the gear 65 and integral therewith is a slow speed pinion 83 which if the gear cage is properly positioned can also mesh with the gear 37 and this combination of gears results in a relatively slow speed for the fuel feed screw. It can thus be seen that when the gear 63 meshes with the gear 37 that no reduction is secured other than that between the gear 37 and the pinion 62 but when the pinion 83 meshes with the gear 37 the reduction is compounded through the gear 65 and when the pinion 82 meshes with the gear 37 the reduction is compounded through the gear 64 providing in effect three different speeds or relations between the motor speed and that of the fuel screw 13. When desiring to change from one speed to another the operator merely moves the looking lever 74 to the position shown in dotted linesin Figure 3 which as stated releases the gear cage which he now rotates manually by means of the knob 75 to thedesired position as indicated by the elevations 78 to and allows the lever 74 to turn to its normal position. It can be seen that by this construction it is impossible for a careless or unskilled operator to injure the mechanism by imperfect handling since the teeth 84 are so shaped as to make it practically impossible for same to jam when meshing. This result is further guaranteed by the fact that they roll into mesh along the entire length of their faces and this movement is extremely slow. One of the outstandin advantages arising from the construction a ove described is the extreme quietness of operation which is obviously desirable when such devices are used in connection with the firing of houshold heating plants.

It has been customary in the existing types of stokers to employ various forms of rachet mechanism for operating the fuel feed screw and to vary the rapidity of the feed by changin the length of the racheting movement or y varying its number of operations or by otherwise controlling the action of the rachet mechanism. Such mechanisms have been found to be objectionable on account of the intermittent nature of their operations as well as on account of the noise which usually accompanies the operation of such mechanisms and still furtherfor the reason that owing to the intermittent nature of their functioning an uneven load is imposed on the motor whereas with the above described device it is uniformly distributed over the entire periods during which the fuel feed screw is in operation.

We are aware that many forms of selective reduction gears have been constructed in the past. It is therefore not our intention to cover such devices broadly but we do intend to cover all such forms and modifications thereof as fall fairly within the appended claims with special reference to their application to under-feed coal burning stokers.

We claim:

1. A selective reduction gear having in combination a housing having a removable cover for the front thereof, a gear cage having a forwardly projecting hub journaling in said front having means on said hub for rotating said cage, said cage having a plurality of holes formed on the front side thereof an index pin slidably mounted on said front having a spring thereon normally urging said pin into one of said holes, a lever attached to said index pin for the purpose of withdrawing same from said holes, a gear cage shaft rotatably mounted within said gear cage and the back of said housing, a worm wheel secured on said gear. cage shaft, a worm shaft journaling in said housing having a worm formed therein meshing with said worm wheel, a drive pinion secured on said gear cage shaft, a plurality of unequal planetary .gears mounted in said gear cage each of which meshes with said drive pinion, some of said planetary gears having planetary pinions joined thereto for the purpose of compounding same, a coun tershaft gear adapted to mesh with a planetary pinion or with the planetary gear not provided with a pinion and means for connecting said countershaft to a fuel feed screw.

2. In a selective reduction gear the combination of a drive pinion with a set of planetary gears disposed around said pinion and constantly meshing therewith, said planetary gears having unequal diameters, certain of said gears having unequal pinions fixedly associated therewith and a driven gear capable of meshing with any one of said pinions or the planetary gears not having any pinions associated therewith as said planetary gears are, revolved about the drive pinion said driven pinion, driven gear and intermediate planetary gears and pinions having their teeth pointed along the entire base thereof to facilitate the meshing of said gears. 3. In a selective reduction gear, a countershaft, a gear loosely mounted on said countershaft, a shear pin securing said gear on 'said countershaft, a gear cage shaft, a drive pinion on said gear cage shaft. a gear cage revolvably mounted on said gear cage shaft, a plurality of planetary gears mounted on said gear cage in constant mesh with said driving pinion,'one of said planetary gears capable of meshing with said countershaft gear, each of the remainder of said planetary gears having a pinion associated therewith in fixed relation thereto, each of said pinions capable of meshing with said countershaft gear when said gear cage is suitably positioned, and means for selectively positioning said gear cage, the teeth onthe countershaft gear as well as the pinions and planetary gear with which it meshes being pointed along their full width to facilitate a rolling engagement of the teeth when meshing.

MARY EVANS PARKER, Emecutm'm of Gyms J. Parker, deceased.

WILLIAM O. JOHNSON. HASKELL C. CARTER. 

